Weekly Hydro-meteorological Report, 11 December, 2014

Highlights

Monitoring and Prediction

Light rainfall was observed throughout the country in the previous week with highest rainfall in the Ampara, Batticaloa and Ratnapura. Northern and north-eastern regions received highly above average rainfall during November while below climatological average rainfall was observed in the rest of the country. Rainfall shall decrease during next week in the entire country but not in a significant level. The northern sea region of Sri Lanka shows a below average sea surface temperature.
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Summary

Monitoring


Weekly Monitoring::On 2nd of December Central province has received around 30 mm rainfall. From 3rd to 7th of December comparatively dry conditions were observed throughout the country with the exceptions of Ampara, Batticloa, Galle and Matara districts that has received around 60 mm rainfall in average. On 8th of December slight rainfall was observed in the entire country in general while Ratnapura district has received high rainfall above 140 mm. Ampara, Batticloa and Ratnapura have received the highest rainfalls during the week.


Monthly Monitoring:An average rainfall of 16 mm-18 mm was observed throughout the country with higher precipitation observed in the north-eastern regions of Sri Lanka during November. Highest rainfall during this month was observed in Northern and Eastern provinces. Also the decadal rainfall average was increased from 14 mm to 18 mm within a week.

Predictions

14-day prediction:NOAA NCEP models predict a decrease in rainfall in the next two weeks compared to previous weeks. The entire country shall receive rainfall around 65 mm during 10th to 16th December. Rainfall shall decrease throughout the country averaging around 25 mm during the week of 17th to 23rd of December.

IMD WRF Model Forecast & IRI forecast:According to the IMD WRF model the entire country shall receive average rainfall up to 7.6 mm on 12th of December. Rainfall is expected to remain the same throughout the country on 13th of December as well while the Western region shall have an increased rainfall up to 64.5 mm.

Seasonal Prediction:As per IRI Multi Model Probability Forecast issued in November for the season December 2014 to February 2015, Rainfall shall remain climatological while the temperature shall be above normal with about 70% probability.

PACIFIC SEAS STATE December 4, 2014 :During October through November the SST exceeded thresholds for weak Niño conditions, although only some of the atmospheric variables indicate an El Niño pattern. Most of the ENSO prediction models indicate weak El Niño conditions during the November-January season in progress, continuing well into the northern spring 2015.
INDIAN OCEAN STATE :Around 0.5 degrees C below average sea surface temperature was observed towards the northern coast.
MJO STATE :MJO is in Phase 7 in Western Pacific and shall slightly enhance the rainfall in Sri Lanka.